Hello all, I have a 2001 with 45k miles, yes I know, I do drive it, and I love the car.
I have had intermittent CEL coming on for about a year or so, each time I reset the code by unplugging the battery and it takes about 5 months to come back on.
The engine does NOT idle rough, it runs perfectly. I went to a shop today because even after battery reset the light was coming on after a few hours of driving so I figured the problem was getting a lot more severe.
He used a snap-on reader and saw 27 multiple fuel trim 2 limit reached and 26 multiple fuel trim 1 limit reached. All other readings were perfect from his reader.
He said I should get a tune up and it may cure it, spark plugs, perhaps coils, etc..
I don't want to blindly change things, especially the MAF which I believe would cause the car to idle very rough if it was bad, and the car idles perfectly and drives beautifully. He reset the code but it came back after 2 minutes of driving.
I have read so many postings and people have many opinions of what to change, ranging from plugs to gaskets to MAF and MAF sensors.
Any thoughts other than a massive overhaul and blind changing of things from this small independent shop here in Massachusetts?

Very much appreciated!
Nelson

09-23-2009, 09:17 AM

Nelson Stacks

Re: 26 and 27 multiple fuel trim 1 and 2 limit reached

It's a 740i, sorry to have not included that before.

09-23-2009, 09:31 PM

tcachtung

Unless you want to throw parts at it you need to

get it diagnosed properly. This could be items that include spark plugs, air filter, fuel filter etc but more than likely you have a vacumme leak. This is best found with a smoke test....smoke is forced into the motor via the intake boot at low pressure which comes out where there are vacumme leaks. Additionally you could have a bad MAS but that is a lot of money on a guess. If you don't have a shop and need one, try www.bimrs.org for a reputable BMW specializing indy. Trent Cole, Tech Advisor, Lone Star Chapter, BMW CCA
President, Lone Star Bavarian, Inc.
FT. Worth Tx, 76132
www.lonestarbavarian.com

09-23-2009, 11:22 PM

claudio512

Re: 26 and 27 multiple fuel trim 1 and 2 limit reached

If you were in Dallas, Texas... Trent Cole would be your solution. However, as he has explained some of the possible problems without adding other engine sensors... I hope you find someone as good as those guys at Lone Star Bavarian in Dallas...